18 GENERAL ZOOLOGY 



Locusts have been and are used to-day as food in various 

 parts of the East. The records on the bricks of Babylon and 

 Nineveh show that they were known in early times as food, 

 and they are mentioned among the clean meats in Leviticus 

 xi. 22. They are in common use among the Arabs and the 

 Bushmen ; our own Rocky Mountain locust has been eaten 

 and pronounced quite palatable. 



Grasshoppers. The insects which so far we have been con- 

 sidering, while often spoken of as grasshoppers, are not true 



FIG. 8. Katydid. Natural size 

 (From Hunter's Studies in Insect Life) 



grasshoppers, though closely allied to them. The locusts 

 have short, rather stout, antennre, while the true grasshoppers 

 have thread-like antennae, much longer than the body. Per- 

 haps the most interesting of the grasshoppers are the katy- 

 dids (Fig. 8), large green insects of arboreal (tree-dwelling) 

 habits, found in the eastern and central United States. 

 They afford an illustration of protective resemblance, a term 

 which is used to cover those cases in which an animal pos- 

 sesses colors or shape which harmonize with its environment 

 (surroundings), or with some particular object in the environ- 

 ment, thus affording protection against enemies. In the case 

 of katydids the whole body is green and the wings are thin 

 and veined like a leaf. The well-known note from which the 

 name " katydid " is derived is produced only by the male, and 



